Gold catalysis and its applications in synthesis of fluorinated organic compounds.

Our research activities are based on the catalytic systems that provide resource-saving synthetic methodologies through gold-catalyzed reactions of alkynes and alkenes. We have worked on three applications: i) an effective and straightforward hydration of 3-alkynoates catalyzed by gold (III); this mild and atom-economical method can be used effectively with a wide range of substrates with high regioselectivity; ii) an efficient monofluorination of allyl silanes using Selectfluor has been achieved without gold catalysts; iii) a fluorine-enabled cationic metal species, generated by fluorination of a low valence gold(l) complex, catalyzed the hydration of alkynes to give a-substituted-a-fluoroketones in one pot under mild conditions. The latter allowed a diverse range of fluorine building blocks or targets to be made available using tools that are amenable in combinatorial or parallel synthesis conditions in drug discovery laboratories or process chemistry

Benzyldimethyldodecyl ammonium chloride shifts the proliferation of functional genes and microbial community in natural water from eutrophic lake

Benzylalkyldimethylethyl ammonium compounds are pervasive in natural environments and toxic at high concentrations. The changes in functional genes and microbial diversity in eutrophic lake samples exposed to benzyldimethyldodecyl ammonium chloride (BAC) were assessed. BAC exerted negative effects on bacteria abundance, particularly at concentrations of 100 mu g L-1 and higher. A significant increase in the number of the quaternary ammonium compound-resistant gene qacA/B was recorded within the 10 mu g L-1 treatment after the first day of exposure. Not all antibiotic resistance genes increased in abundance as the concentrations of BAC increased; rather, gene abundances were dependent on the gene type, concentrations of BAC, and contact time. The nitrogen fixation-related gene nifH and ammonia monooxygenase gene amoA were inhibited by high concentrations of BAC after the first day, whereas an increase of the nitrite reductase gene nirK was stimulated by exposure. Microbial communities within higher treatment levels (1000 and 10 000 mu g L-1 ) exhibited significantly different community composition compared to other treatment levels and the control. Selective enrichment of Rheinheimera, Pseudomonas, and Vogesella were found in the higher treatment levels, suggesting that these bacteria have some resistance or degradation capacity to BAC. Genes related with RNA processing and modification, transcription, lipid transport and metabolism, amino acid transport and metabolism, and cell motility of microbial community function were involved in the process exposed to the BAC stress. (C) 2018 Elsevier Ltd. All rights reserved.</p

Exploring transcriptional signalling mediated by OsWRKY13, a potential regulator of multiple physiological processes in rice

BACKGROUND Rice transcription regulator OsWRKY13 influences the functioning of more than 500 genes in multiple signalling pathways, with roles in disease resistance, redox homeostasis, abiotic stress responses, and development. RESULTS To determine the putative transcriptional regulation mechanism of OsWRKY13, the putative cis-acting elements of OsWRKY13-influenced genes were analyzed using the whole genome expression profiling of OsWRKY13-activated plants generated with the Affymetrix GeneChip Rice Genome Array. At least 39 transcription factor genes were influenced by OsWRKY13, and 30 of them were downregulated. The promoters of OsWRKY13-upregulated genes were overrepresented with W-boxes for WRKY protein binding, whereas the promoters of OsWRKY13-downregulated genes were enriched with cis-elements putatively for binding of MYB and AP2/EREBP types of transcription factors. Consistent with the distinctive distribution of these cis-elements in up- and downregulated genes, nine WRKY genes were influenced by OsWRKY13 and the promoters of five of them were bound by OsWRKY13 in vitro; all seven differentially expressed AP2/EREBP genes and six of the seven differentially expressed MYB genes were suppressed by in OsWRKY13-activated plants. A subset of OsWRKY13-influenced WRKY genes were involved in host-pathogen interactions. CONCLUSION These results suggest that OsWRKY13-mediated signalling pathways are partitioned by different transcription factors. WRKY proteins may play important roles in the monitoring of OsWRKY13-upregulated genes and genes involved in pathogen-induced defence responses, whereas MYB and AP2/EREBP proteins may contribute most to the control of OsWRKY13-downregulated genes.This work was supported by grants from the National Program of High Technology Development of China, the National Program on the Development of Basic Research in China, and the National Natural Science Foundation of China

Bright room temperature single photon source at telecom range in cubic silicon carbide

Single photon emitters (SPEs) play an important role in a number of quantum information tasks such as quantum key distributions. In these protocols, telecom wavelength photons are desired due to their low transmission loss in optical fibers. In this paper, we present a study of bright single-photon emitters in cubic silicon carbide (3C-SiC) emitting in the telecom range. We find that these emitters are photostable and bright at room temperature with a count rate of ~ MHz. Together with the fact that SiC is a growth and fabrication-friendly material, our result may pave the way for its future application in quantum communication technology applications.Comment: Accepted by Nature Communication

High-efficiency generation of nanoscale single silicon vacancy defect array in silicon carbide

Color centers in silicon carbide have increasingly attracted attention in recent years owing to their excellent properties such as single photon emission, good photostability, and long spin coherence time even at room temperature. As compared to diamond which is widely used for holding Nitrogen-vacancy centers, SiC has the advantage in terms of large-scale, high-quality and low cost growth, as well as advanced fabrication technique in optoelectronics, leading to the prospects for large scale quantum engineering. In this paper, we report experimental demonstration of the generation of nanoscale $V_{Si}$ single defect array through ion implantation without the need of annealing. $V_{Si}$ defects are generated in pre-determined locations with resolution of tens of nanometers. This can help in integrating $V_{Si}$ defects with the photonic structures which, in turn, can improve the emission and collection efficiency of $V_{Si}$ defects when it is used in spin photonic quantum network. On the other hand, the defects are shallow and they are generated $\sim 40nm$ below the surface which can serve as critical resources in quantum sensing application

Detect Copy Number Variations from Read-depth of High-throughput Sequencing Data

Copy-number variation (CNV) is a major form of genetic variation and a risk factor for various human diseases, so it is crucial to accurately detect and characterize CNVs. High-throughput sequencing (HTS) technologies promise to revolutionize CNV detection but present substantial analytic challenges. This dissertation investigates improving the CNV detection using HTS data mainly from the following aspects. It is observed that various sources of experimental biases in HTS confound read-depth estimation, and bias correction has not been adequately addressed by existing methods. This dissertation presents a novel read-depth-based method, GENSENG, which identify regions of discrete copy-number changes while simultaneously accounting for the effects of multiple confounders. It is conceivable that allele-specific reads from HTS data could be leveraged to both enhance CNV detection as well as produce allele-specific copy number (ASCN) calls. Although statistical methods have been developed to detect CNVs using whole-genome sequence (WGS) and/or whole-exome sequence (WES) data, information from allele-specific read counts has not yet been adequately exploited. This dissertation presents an integrated method, called AS-GENSENG, which incorporates allele-specific read counts in CNV detection and estimates ASCN using either WGS or WES data. Although statistically powerful, the GLM+NB method used in GENSENG and AS-GENSENG has a quadric computational complexity and therefore suffers from slow running time when applied to large-scale sequencing data. This dissertation aims to substantially speed up the GLM+NB method by using a randomized algorithm and demonstrate the utility of our approach by providing R-GENSENG, a speeded up version of GENSENG.Doctor of Philosoph

System Identification Algorithm Analysis of Acupuncture Effect on Mean Blood Flux of Contralateral Hegu Acupoint

Background. Acupoints (belonging to 12 meridians) which have the same names are symmetrically distributed on the body. It has been proved that acupoints have certain biological specificities different from the normal parts of the body. However, there is little evidence that acupoints which have the same name and are located bilaterally and symmetrically have lateralized specificity. Thus, researching the lateralized specificity and the relationship between left-side and right-side acupuncture is of special importance. Methodology and Principal Findings. The mean blood flux (MBF) in both Hegu acupoints was measured by Moor full-field laser perfusion imager. With the method of system identification algorithm, the output distribution in different groups was acquired, based on different acupoint stimulation and standard signal input. It is demonstrated that after stimulation of the right Hegu acupoint by needle, the output value of MBF in contralateral Hegu acupoint was strongly amplified, while after acupuncturing the left Hegu acupoint, the output value of MBF in either side Hegu acupoint was amplified moderately. Conclusions and Significance. This paper indicates that the Hegu acupoint has lateralized specificity. After stimulating the ipsilateral Hegu acupoint, symmetry breaking will be produced in contrast to contralateral Hegu acupoint stimulation